Indicators of Oxidative Stress and Antioxidant Activity in the Comorbidity of Non-Alcoholic Fatty Liver Disease and Arterial Hypertension

It is known that oxidative stress is one of the most important pathogenetic mechanisms of cardiovascular diseases. Its role in the development and progression of chronic liver and kidney diseases is also well known.
The purpose of the work was to study the state of lipid peroxidation and antioxidant protection in patients with non-alcoholic fatty liver disease and its comorbidity with essential hypertension or renoparenchymal arterial hypertension, as well as assess the main factors affecting antioxidant defense in this category of patients.
Material and methods. The object of the study was 269 patients, including 60 patients with non-alcoholic fatty liver disease, 121 patients with comorbidity and essential hypertension, 88 patients with comorbidity and renoparenchymal arterial hypertension. The control group consisted of 20 healthy individuals. Clinical examination of patients included an assessment of the objective examination parameters, in particular, anthropometric data and blood pressure according to standard methods. We used an ultrasonic research method (ultrasound scanner "GE", USA). Blood biochemical parameters were determined according to standard generally accepted methods: ALT, total cholesterol, insulin levels with the determination of the HOMA index, adiponectin levels, tumor necrosis factor-α concentration, glomerular filtration rate according to the CKD-EPI formula. The state of the prooxidant system was evaluated by the levels of diene conjugates and malondialdehyde, and the state of the enzymatic antioxidant defense system was assessed by the activity of superoxidedismutase.
Results and discussion. We found a significant increase in both indicators of oxidative stress in all three groups compared to the control group (p <0.001). In addition to an increase in lipid peroxidation, we observed a decrease in superoxidedismutase in the studied patients. It was most significant in the group of comorbidity with renoparenchymal arterial hypertension – 25.15 ± 3.28 U / mg Hb min. The influence of oxidative stress indicators on almost all parameters that were investigated in non-alcoholic fatty liver disease and its comorbidity with arterial hypertension was revealed. Differences were recorded, mainly according to blood pressure, total cholesterol, body mass index and glomerular filtration rate.
According to analysis of variance MANOVA, a significant effect of the factor “non-alcoholic fatty liver disease” and the factor “arterial hypertension” on each of the three indicators of the lipid peroxidation system and antioxidant defense (p <0.001) was found.
In our opinion, the fact that the indicators of oxidative stress are strongly influenced not only by each factor individually, but also by their interaction is very important. The most powerful effect was found for the indicator of superoxidedismutase - F = 40.9 (p <0.001).
Conclusion. Thus, the processes of lipid peroxidation and antioxidant protection are disrupted in patients with non-alcoholic fatty liver disease. Comorbidity with essential hypertension or renoparenchymal arterial hypertension makes these disorders more pronounced, which can affect both the onset and course of these diseases. The spectrum of significant correlation is different between patients with isolated non-alcoholic fatty liver disease and its comorbidity, which may indicate several different pathogenetic mechanisms of the onset and progression of these diseases. When non-alcoholic fatty liver disease with essential hypertension or renoparenchymal arterial hypertension is comorbid, disturbances in lipid peroxidation and antioxidant defense are associated with the mutually beneficial effect of these nosologies.